Anticorrosive lubricating oil and a process of fractionating alkali and alkaline earth metal petroleum sulfonates



Patented Mar. 7, 1950 ANTICORROSIVE LUBRICATING OIL AND A PROCESS OFFRACTIONATING ALKALI AND ALKALINE EARTH METAL PETRO- LEUM SULFONATESChester E. Wilson, San Pedro, Calif., assignor to Union Oil Company ofCalifornia, Los Angelel, Calif., a corporation of California No Drawing.Application April 6, 1945, Serial No. 587.021

17 Claims.

This invention relates to a method of treating suifonated mineral orfatty oils, which sulfonates find wide application in the preparation ofanticorrosion agents. More particularly the invention relates to new andimproved rust preventive oils containing sulfonated oils, treated by themethod as hereinafter described.

When metals are stored, especially in the form of finished articles,composed in whole or in part of metals. particular care is required toprotect the surfaces from corrosion. Several types of rustpreventive'compositions have been developed with the express purposes ofpreventing this corrosion during storage. One such type of rustpreventive composition, which usually contains a large proportion ofpetrolatum, deposits a waxy or unctuous film on the metal surfaces bydipping the article in the molten rust preventive. Another type, whichcontains compounds dissolved in a volatile solvent, leaves an imperviousfilm on the sprayed or dipped article after evaporation of the solvent.The protective coating from the second type may result by simpleevaporation of the solvent or by oxidation and drying of the compoundsin the rust preventive composition. Such compositions may containsulfonated mineral oils as anticorrosion agents.

In addition to the above types of rust preventive compositions are theequally important ones of anticorrosive lubricating oils and greasesemployed in the lubrication and storage of machinery, engines, parts,tools, and the like. These compositions have the property, in additionto lubrication, of inhibiting the corrosion of metal surfaces of suchequipment. These anticorrosive lubricating oils generally contain amineral oil and from 1% to and more often in the range of from 2% to 5%of metal soap of a petroleum sulfonic acid. In conjunction with theseconstituents various additives are often employed such as otheranticorrosive agents for example degras or lanolin, pourpointdepressants comprising for example Friedel-Crafts condensation productsof chlorinated waxes and aromatics, antioxidants such as thethiophosphates and the phenol sulfide soaps or salts, viscosity indeximprovers as for example polyisobutylene and the polymerized higheresters of methyl acrylic acid, and foam suppressors or inhibitors. Agrease containing an anticorrosion agent would be comprised ofessentially the above ingredients with the addition thereto of a metalsoapof a fatty acid as the thickening agent.

Anticorrosive lubricating oils and greases of this class findapplication both in the lubrication of metal bearings and as a coatingto prevent rusting of metal articles during storage. In this latter casethese lubricating oils have an advantage over the coating compounds asabove described in that it is not necessary that they be removed fromthe metal parts prior to usage. Such anticorrosive lubricating oils andgreases must fulfill not only the qualifications of a good lubricant:that is of a conventional lubricant not possessing anticorrosiveproperties such as stability towards oxidation at high temperatures,resistance to decomposition at high temperatures and resistance toseparation at low temperatures, but further they must exhibitanticorrosive properties during exposure to h gh relative humidity, toadverse weather conditions, and to marine atmospheres.

High humidity may be encountered by machinery or other metal parts byexposure to atmospheric conditions of high humidity which occurparticularly in the tropics. It is a particular function of ananticorrosion agent therefore to resist .this high humidity inasmuch asthe rate of rusting appears to be a function of the degree of humidity.For such purposes either of the two types of anticorrosion agentsdescribed may be employed. However, high humidity is also encountered ininternal combustion engines when the engines are in the process ofcooling, the relative humidity increasing rapidly with a decrease intemperature. For protection from corrosion under such conditions theanticorrosion lubricants must be employed inasmuch as they must not onlyprotect the vital parts from rusting under these conditions of inducedhigh humidity but they must lubricate the contactin surfaces when themotor is in operation.

It is a particular object of my invention to provide anticorrosionlubricants which have bet-.

ter resistance to conditions of high humidity or actual condensation,which may occur under such conditions, and further to provide a processwhereby such improved anticorrosion lubricants may be prepared.

It is a more particular object of my invention to prepare anticorrosionlubricants having improved resistance to humidity by treating thesulfonate soaps employed as the anticorrosion agents in such lubricantsby a simple and economical manner.

Another object of the invention is to provide a simple and economicalprocess for extracting the metal soaps and particularly the alkali oralkaline earth metal soaps of the petroleum sulfonates in such a manneras to produce a railinate which when incorporated in an anticorrosionlubricant is capable of imparting thereto improved resistance tohumidity over that which would result if the untreated sulfonate wereemployed.

Other objects and advantages of my invention will become apparent tothose skilled in th art as the description thereof proceeds.

I have found that the commercially available 3 organic sulionates, thatis the metal soaps .oi' the organic sulfonic acids, in particular, thepetroleum sulfonic acids. are inadequate for the preparation ofanticorrosive lubricating oils and greases. Their inadequacy iswitnessed in the failure of rust preventive compounds employing thesemetal soaps to pass specified corrosion tests. I have found that thisdiinculty can be remedied by treating the suli'onates, which term willhereinaiter be employed to designate the metal soaps of the sulionicacids, with a solid adsorbent which has the effect or adsorbing acertain proportion of the suli'onate. The composition of that part ofthe sulionate which is adsorbed is as yet unknown but the raillnate inthis adsorption when included in a suitable lubricating oil base willgive a product which passes all the tests required for suchanticorrosive lubricating oils.

As adsorbents for this purification I have found to be effective suchmaterials as the clays including bentonite, kaolin, kaolinite, ballclays and the like, the aluminas, either naturally occurring orsynthetic such as bauxites, synthetic activated alumina and the like,synthetic aluminum silicates, silica gel, magnesia, other metal oxidesor hydrous oxides, natural adsorbents such as fuller's earth, and thelike, and carbon adsorbents such as charcoal, coke, coal and the like.or this group I have found the clays, and particularly the hentoniticclays of montmorillonite structure are the best adsorbents from achemical as well as a practical standpoint.

I may efiect the treatment of the sulfonates with these adsorbents inany desired manner such as batchwise contact, percolation through a bedof such adsorbent, countercurrent extraction and the like. In thisregard I have observed that during the percolation ofthe suli'onatesthrough a bed of adsorbent such as a bentonitic clay, a stratificationoccurs suggesting the possibility of a chromotographic separation.However, such separation of the various strata is not an essentialelement of my process inasmuch as I have determined that there is anoptimum amount of sulfonate to be removed from the original feed to givea satisfactory product and a separation of the removed sulfonate intovarious constituents will have no effect on the rafllnate from theextraction.

In most cases it is desired to employ a solvent in conjunction with thesulfonate to be treated to facilitate the treating operation. Thecommercially available sulfonates generally consist of solutions of thesulfonate in a mineral oil, the sulfonate being present to the extent offrom 50% to 70%. in the solution, which solution of sulfonate in mineraloil will hereinafter be referred to as sulfonate solution.

This sulfonate solution may if desired be contacted, as such, with thedesired adsorbent but I have found that the treatment is more effectiveif the sulfonate solution is further diluted with a non-polar solventsuch as a light hydrocarbon or the oil to be used in the resultantantlcorrosion lubricating oil. This latter type of dilution probablyrepresents the best method of procedure inasmuch as there is nonecessity of separating the treated sulfonate from the solvent diluentprior to its incorporation as the anticorrosion agent in a lubricatingoil or ease.

Further, I have found that the extraction is more eifective if carriedout at an elevated temperature such as from about 200 F. to about 3501''. This temperature appears to be a function of the solvent employed,that is with a lighter solvent a lower temperature will eifect the samedegree of extraction as a higher temperature with a heavier solvent. Onthis basis it would appear that the temperature plays an important partnot only in activating the adsorption but in relation to the eventualproduct as a result of a decrease in the viscosity of the solution to betreated incurred by an increase in temperature. I do not wish to belimited, however, to the temperature range of 200' I". to 350' l".inasmuch as temperatures below and above this range are also eifectivebut I shall avoid excessive temperatures, such as above 450 E, whichcause a detrimental change in the characteristics of the sulionate. Asshown in Example 1 hereinbelow the extraction may be satisfactorilycarried out at temperatures as low as 100 1''.

After the extraction the adsorbent may be reactivated and the extractedsulionate may be recovered in any desired manner. I have found that thismay be accomplished simply and effectively by extracting the adsorbentwith a polar solvent to selectively displace the sulfonate from theclay. The adsc bent, preferably in the presence of the next batch ofsulfonate to be purified, is subsequently heated to a temperaturesufilcient to remove the solvent by evaporation, the solvent vaporsbeing condensed and recovered to be re-employed. and the solventextracted suifonate is heated in a similar manner to remove the solventtherefrom. This extract if completely freed of the polar reactivatingsolvent will be in the form of a comparatively pure powdered sulfonate.For this reason it may be desirable to dilute the solvent-'sulfonatemixture with a mineral oil prior to evaporating the solvent therefrom.For this reactivation I may employ any polar solvent such as the lowmolecular weight alcohols and ketones or other low molecular weightcompounds containing polar groups. The reactivation is simplified byemploying a low boiling polar solvent in that heat requirements for itsrecovery from the adsorbent and extract are considerably less than ifhigh boiling solvents are employed. The preferred solvent for thereactivation of the adsorbent is isopropyl alcohol because of theresulting effective displacement of the sulfonate from the adsorbent.ease of handling, and its low cost. It is,however, to be understood thatI do not intend to be limited to the use of this one solvent as I havefound many other low molecular weight polar solvents particularly thealcohols and ketones to be eifective.

Generally the petroleum sulfonates are prepared by treating a mineraloil fraction in the lubricating oil range in successive stages withsulfuric acid. These lubricating oil fractions to be sulfonated varywidely in such characteristics as parafiinicity, viscosity index and thelike. The acid concentration is increased in each successive stage ofthe sulfonation until fuming acid is employed in the later stages togive the mahogany acids. These mahogany acids are neutralized with.caustic to give the mahogany soaps or sulfonates and are extracted fromthe oil with aqueous alcoholic solutions. A more complete description ofthe general process is difiicult due to the many modifications that maybe employed. A second method of sulfonation consists in treating themineral oil with sulfur trioxide which treatment may be at high or lowtemperatures and with or without other solvents being present. In anycase, however, the sulfonated products usually consist of the mahoganysulfonic acids and green acids.

, version of the latter to the metal sulfonates for use as anticorrosionagents. Herein lies a possible explanation for the effectiveness of thepuriflcation of the sulfonates according to my invention. It is possiblethat green acids remain in the majority of mahogany sulfonic acidscausing the failure of the resulting anticorrosion agents, and thatthemetal soaps of these green acids are removed in the adsorption processas herein described.' It is to be understood that this is only apossible explanation of the beneficial effect realized in the adsorptionprocess and I do not wish to be limited thereby.

In the extraction of these sulfonates I have found that it is desirableto eifect the removal of from 15% to 30% by weight of the sulfonate inorder to obtain an effective anticorrosion agent. which upon compoundingwith a suitable lubricating oil will pass the necessary specifications.In this regard I have found that the improvement in the oil with respectto resistance to humidity and condensation is a function of the per centsulfonate extracted up to a point, after which no further improvementcan be detected by presently known test methods. That is if I remove ofthe sulfonate in the extraction process an improvement in the resultantanticorrosion lubricant results which, however, is insumcient to meetthe necessary requirements, and for this reason I have established thedesired range of sulfonate removal of about 15% to 30%, a removal inthis range being sufiicient to give a product of the necessaryqualifications. However, it is to be understood that more stringentpurification may be applied, that is an extraction in excess of 30% maybe accomplished without departing from the scope of this inventioninasmuch as this range was merely established as a critical range belowwhich the extraction was beneficial but insufficient to meet presentlyemployed test methods. Thus if requirements for anticorrosion lubricantsshould become more rigorous and test methods are developed or employedwhich reveal greater differentials in such anticorrosion lubricants itmay be desired to increase the degree of extraction to a figure about30%.

On the other hand, with some, particular petroleum sulfonates theconcentration of undesirable components may be relatively low, and itwill be necessary to remove a correspondingly small proportion by thepurification procedure.

Further, I have found that it is not necessary to replace this 15% to30% of removed petroleum sulfonate with additional purified sulfonate inorder to produce an excellent anticorrosive product. Thus ananticorrosive lubricant, requiring for example 3.25% of a petroleumsulfonate may find use in certain applications although it does not meetthe rigid requirements as hereinbefore referred to, and if I treat thesulfonate according to the process of this invention removing, forexample, 30% thereof a subsequent oil containing only-the remaining 70%or 2.28% sulfonate will be more efiective than the original composition.Thus as I remove a given percentage of sulfonate by extraction theconcentration required in an anticorrosive lubricating oil is at leastcorrespondingly reduced and in some cases is reduced below thisproportional amount. Further than this I have found that the extractedsulfonate after removal from the for a period of at least 150 hours.

adsorbent by any process, as for example the one hereinbefore described,may be utilized in applications other than anticorrosive agents such asfor example soluble cutting oils and the like. In the following examplesthe humidity test method as set up in the Government SpecificationAN-VV-C-576a is employed to ascertain the improvements in theanticorrosion lubricants containing the sulfonates treated according tomy invention.

Standard test procedure according to this specification requires thattwo 2-inch by 4-inch by 5-inch sand-blasted panels of steel shall bedipped in a suitable sample of the anticorroslve oil so as to completelysubmerge all surfaces. The panels are then suspended vertically by glasshooks for at least four hours in an atmosphere maintained at a relativehumidity of from 50% to 55% and at a temperature of 25 Cl -3 C. At theend of this period the panels are suspended vertically in a humiditycabinet maintained at a relative humidity of to at a temperature of 49C. :3 C.

The conditioned air is passed through the cabinet at a rate of '7 feetto 9 feet per hour. At the expiration of the test the panels areremoved, cleaned with naphtha and examined, and if these panels show anyevidence of corrosion, pitting or other attack involving either surfacewithin A; inch from any edge they are considered as having failed thetest.

There is still speculation in regard to the mechanism of rusting. It isheld by some that rusting does not occur until the humidity at thesurface of the metal is 100% that is until actual condensation occurs.Others however maintain that the rusting occurs as a result of thehumidity of the atmosphere, as distinguished from actual condensation onthe metal, and that higher humidities accelerate the rusting. This testis, however, designed to provide both of these conditions and it isapparent that an improvement in the resistance of an oil to either is animprovement in resistance to both.

Example I In one example of the effectiveness of th s purificationprocess to improve the resistance of anticorrosion lubricants tohumidity and condensation an anticorrosive compound was preparedcomprising 1S% of a 60% solution of sodium soap of petroleum sulfonicacid, 10.5% of a 20% solution of an antioxidant, in this case thecalcium salt 'of amylphenol sulfide, and 76.5% of a SAE 40 lubricatingoil. This composition was diluted with three parts of Navy Symbol 1120oil and then subjected to the test as above described. Navy Symbol 1120oil as herein referred to consists of a paraflinic mineral oilconforming to certain Navy specifications but generally defined ashaving a viscosity of seconds at 210 F. by the Saybolt Universal methodof viscosity determination and a minimum viscosity index of 95. Thisinitial composition containlng the untreated sulfonates failed the abovetest in that considerable corrosion of the test panels resulted.

A second composition was prepared in which one part of the'same sodiumsoap of petroleum sulfonic acids was treated in the presence of fourparts of light hydrocarbon with one part of bentonitic clay at atemperature of 100 F. removing thereby 17% of the sulfonate as evidencedby a sulfate ash of 8.3% after removal of the light hydrocarbon solventas compared to a sulfate ash of 10% in the original material. Thistreated sulfonate comprising after treatment and removal of lighthydrocarbon solvent 49.8% sulfonate in mineral oil was incorporated in alubricating oil as follows: 15.7% of the treated sulfonate solution,10.5% of a solution of the calcium salt of amylphenol sulfide, 73.8 ofan SAE 40 lubricating oil. This mixture having the same composition asthat in the first part of this example by virtue of adjusted proportionscompensating for the change in composition of the sulfonate solutionswas again diluted with three parts of Nav Symbol 1120 oil and subjectedto the above described test with no evidence of corrosion on the testpanels at the termination thereof, indicating the improvement of thefinal oil in regards to its resistance to high humidity brought about bythe treatment of the sulfonate.

Example II Another sample of a mineral oil solution of sodium soap of apetroleum sulfonic acid was clay treated at 300 F. in the presence of 4parts of an SAE 40 lubricating oil to reduce the sulfate ash content ofthe mixture from 2.0% to 1.35% or a reduction of 32.5%, and 65 parts ofthis mixture was mixed with 10.5 parts of a 20% solution of the calciumsalt of amylphenol sulfide and 24.5 parts of the same SAE 40 lubricatingoil as employed as a diluent in the extraction resulting in acomposition containing 5.25 of sulfonate,-on an oil free basis, 5.2% oilfrom the original sulfonate solution, 10.5% of the amylphenol sulfidesolution and 79.05% of SAE 40 lubricating oil.

A second composition was prepared using 13% of untreated sulfonatesolution, equivalent to 7.8% of sulfonate on an oil free basis, 10.5% ofthe 20% solution of calcium salt of amylphenol sulfide and 76.5% of theSAE 40 lubricating oil, as in the above example, and these twocompositions were diluted with.3 parts Navy Symbol 1120 lubricating oiland tested according to the specifled procedure. In this test the oilcontaining the treated sulfonate passed without sign of corrosion, whilethe one containing untreated sulfonate failed because of corrosion of thtest panels. It should be noted that the oil containing treatedsulfonate passed the test in spite of the presence of only 68% as muchsulfonate as present in the second composition which failed the test.This type of test has been repeated a number of times with thoroughlyconsistent results, that is those compositions containing a sulfonatefromwhich has been removed at least 15% of the sulfonate by extractionwith the solid adsorbent have resulted in compositions which universallypass the above test, while those compositions containing an untreatedsulfonate universally fail the above test.

Although my preferred method of treating thesepetroleum sulfonate soapsto obtain a fraction thereof which is superior to the originalsulfonatein imparting properties of resistance to corrosion underconditions of high humidity is by contacting these alkali and alkalineearth metal soaps of the petroleum sulfonic acids with a solid adsorbentas hereinbefore described, I have also found that the sulfonates may beextracted with other extractive agents comprising organic solvents toaccomplish much the same effect. As solvents for this extraction I mayemploy the various alcohols and ketones and particularly the lowmolecular weight alcohols and ketones such as isopropyl alcohol, ethylalcohol, butyl alcohol, methyl ethyl ketone, methyl isopropyl ketone andthe like or mixtures of these. These solvents may be employed in anyknown type of solvent extraction process such as countercurrent,concurrent, batchwise, continuous or the like to separate the sulfonateinto a more desirable and a less desirable traction on the basis of thehumidity resistance of the anticorrosion lubricants in which they may beemployed.

The foregoing description and examples of the invention are not to betaken as limiting since many variations may be made by those skilled inthe art without departing from the spirit or scope of the followingclaims.

I claim:

1. A process for treating soaps selected from the class consisting ofthe alkali and alkaline earth metal soaps of sulfonated mineral oils toimprove their resistance to humidity which comprises contacting amineral oil solution of said soaps at a temperature between about F. andabout 450 F. with a sufiicient amount of a solid adsorbent to extractbetween about 5% and 30% of said soaps therein having a comparativelylower resistance to humidity.

2. A process for treating the alkali metal soaps of sulfonated mineraloils to improve their resistance to humidity which comprises contactinga mineral oil solution of said soaps at a temperature between about 100F. and about 450 F. with a suflicient amount of a solid adsorbent toextract between about 5% and 30% of said soaps therein having acomparatively lower resistance to humidity.

3. A process for treating the sodium soaps of petroleum sulfonic acidsto improve their resistance to humidity which comprises contacting amineral oil solution of said metal soaps at a temperature between about100 F. and about 450 F. with a suflicient amount of a solid adsorbent toextract between about 5% and 30% of said soap therein having acomparatively lower resistance to humidity.

4. A process for treating one of a group consisting of the alkali andalkaline earth metal soaps of petroleum sulfonic acids to improve theirresistance to humidity which comprises contacting a mineral oil solutionof said metal soaps at a temperature between about 100 F. and about 450F. with a sufllcient amount of clay to extract between about 5% and 30%of said soaps therein having a comparatively lower resistance tohumidity;

5. A process for the separation of soaps selected from the classconsisting of the alkali and alkaline earth metal soaps of sulfonatedmineral oils into a fraction having a high resistance to humidity and afraction having relatively lower resistance to humidity than theoriginal sulfonate which comprises contacting a mineral oil solution ofsaid soaps with a quantity of a solid adsorbent to remove at least fromabout 5 to about 30% of said soaps at a temperature between about 100 F.and about 450 F., separating the rafilnate or improved fraction fromsaid adsorbent, washing said adsorbent with a polar solvent to recoverthe soap extract and heating said sulfonated oil extractto recover thesolvent therefrom.

6. A process for the separation of the alkali metal soaps of a petroleumsulfonic acid into a fraction having a high resistance to humidity and afraction having relatively lower resistance to humidity than theoriginal sulfonate which comprises contacting a mineral oil solution orsaid petroleum sulfonate with a sufllcient quantity of a solid adsorbentto remove at least from about to about 30% 01' said petroleum sulfonatesoaps at a temperature between about 100 F. and about 450 F. separatingthe rafllnate or improved fraction from said adsorbent, washing saidadsorbent with a polar solvent to recover the petroleum sulfonateextract and heating said petroleum sulfonate extract to recover thesolvent therefrom.

7. A process for the separation of an alkali metal soap of a petroleumsuli'onic acid into a fraction having a high resistance to humidity anda fraction having a relatively lower resistance to humidity than theoriginal sulfonate which comprises contacting a mineral oil solution ofsaid metal soap of a petroleum sulfonic acid at a temperature betweenabout 100 F. and about 450 F. with a sumcient quantity of clay to effectthe removal 01' at least from about 15% to about 30% of said metal soapoi the petroleum sulfonic acids, and separating the ramnate or improvedfraction from the resulting adsorbent.

8. A process for the separation of an alkali metal soap of a petroleumsulfonic acid into a fraction having a high resistance to humidity and afraction having a relatively lower resistance to humidity than theoriginal suli'onate which comprises contacting a mineral oil solution ofsaid metal soap of a petroleum sulionic acid at a temperature betweenabout 100 F. and about 450 F. with a sufllcient quantity oi! silica gelto eil'ect the removal of at least from about 15% to about 30% of saidmetalsoap oi the petroleum suli'onic acid, and separating the raiilnateor improved fraction from the resulting adsorbent.

9. A process for the separation 01' an alkali metal soap of a petroleumsuli'onic acid into a fraction having a high resistance to humidity anda fraction having a relatively lower resistance to humidity than theoriginal suli'onate which comprises contacting a mineral oil solution ofsaid metal soap of a petroleum sulionic acid at a term perature betweenabout 100 F. and about 450 F. with a suilicient quantity of charcoal toeilect the removal of at leastirom about 15% to about 30% of said metalsoap of the petroleum sulfonic acid, and separating the rafllnate orimproved fraction from said adsorbent.

10. A process for the separation of the alkali metal soaps of petroleumsulfonic acid into a fraction having a high resistance to humidity and afraction having a relatively lower resistance to humidity than theoriginal sulfonate which comprises contacting a mineral oil solution ofsaid petroleum suli'onate with a sufllcient quantity of a solidadsorbent to remove at least from about 15% to about 30% of saidpetroleum sulionate soap at a temperature between about 100 F. and about450 F., separating the ramnate or improved fraction from said adsorbent,washing said adsorbent with isopropyl alcohol to recover the petroleumsultonate extract and heating said petroleum sulfonate extract torecover the solvent therefrom.

11. A process for the separation of the alkali metal soaps oi petroleumsulfonic acid into a fraction having a high resistance to humidity and afraction having a relatively lower resistance to humidity than theoriginal sulionate which comprises contacting a mineral oil solution oisaid petroleum sulionate with a sumcient quantity oi a clay adsorbent toremove at least from about 15% to about 30% of said petroleum sulfonatesoap at a temperature between about 100 F. and about 450 F., separatingthe rafllnate or improved fraction from said adsorbent, washing saidadsorbent with a polar solvent to recover the petroleum sulfonateextract and heating said petroleum sulfonate extract to recover thesolvent therefrom.

12. An anticorrosive lubricating oil having high resistance to humidityconsisting essentially of a lubricating oil and soaps selected from theclass consisting of the alkali and alkaline earth metal soaps ofpetroleum sulfonic acids, which petroleum sulfonate soap is obtained asthe raffinate from the treatment of a mineral oil solution of thecorresponding untreated soap of a petroleum sulfonic acid at atemperature between about 100 F. and about 450 F. with a substantialamount of a solid adsorbent so as to extract between about 5% and 30% ofthe soaps therein having a comparatively lower resistance to humidity.

13. An anticorrosive lubricating oil having high resistance to humidityconsisting essentially of a lubricating oil and an alkali metal soap ofa petroleum sulfonic acid, which petroleum sulfonate soap is obtained asthe raflinate from the treatment of a mineral oil solution of an alkalimetal soap of a petroleum sulfonic acid at a temperature between about100 F. and about 450 F. with a substantial amount of a solid adsorbentso as to extract between about 5% and 30% of the soaps therein having acomparatively lower resistance to humidity.

14. An anticorrosive lubricating oil having high resistance to humidityconsisting essentially of a lubricating oil and a sodium soap of apetroleum sulionic acid, which petroleum sulionate soap is obtained asthe raflinate from the treatment of a mineral oil solution of a sodiumsoap oi a petroleum sulfonic acid with a quantity of a solid adsorbentat a temperature between about 100 F. and about 450 F. so as to extractat least from about 15% to about 30% of said soap.

15. A process according to claim 4 in which the contacting temperatureis between about 200 F. and about 350 F.

16. A process according to claim 4 in which the metal soaps in solutionin mineral oil are diluted with a light hydrocarbon traction and theresulting solution is contacted with clay.

17. Ananti-corrosive lubricating 011 according to claim 12 in which saidmineral oil solution of .untreated soap is diluted with a lighthydrocarbon fraction and the resulting solution contacted with solidadsorbent.

CHESTER E. WILSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Barbour Feb. 26, 1946

12. AN ANTICORROSIVE LUBRICATING OIL HAVING HIGH RESISTANCE TO HUMIDITYCONSISTING ESSENTIALLY OF A LUBRICATING OIL AND SOAPS SELECTED FROM THECLASS CONSISTING OF THE ALKALI AND ALKALINE EARTH METAL SOAPS OFPETROLEUM SULFONIC ACIDS, WHICH PETROLEUM SULFONATE SOAP IS OBTAINED ASTHE RAFFINATE FROM THE TREATMENT OF A MATERIAL OIL SOLUTION OF THECORRESPONDING UNTREATED SOAP OF A PETROLEUM SULFONIC ACID AT ATEMPERATURE BETWEEN ABOUT 100*F. AND ABOUT 450*F. WITH A SUBSTANTIALAMOUNT OF A SOLID ADSORBENT SO AS TO EXTRACT BETWEEN ABOUT 5% AND 30% OFTHE SOAPS THEREIN HAVING A COMPARATIVELY LOWER RESISTANCE TO HUMIDITY.